Laser apparatus and method for processing objects with a laser which is controllable in terms of the pulse energy

1. A laser processing apparatus for laser processing of an object, comprising: a pulsed laser controllable with regard to laser pulse energy and a temporal retrieval of laser pulses, said pulsed laser having an energy control input for receiving an analog signal with a voltage controlling the laser pulse energy, and a retrieval input for receiving a signal by means of which a retrieval of the laser pulses is controllable temporally; a control device, configured to generate, on a basis of processing information, a pulse energy signal which, in a manner temporally correlated with a clock signal assumes voltage values which represent the laser pulse energy for the laser pulses which are retrievable by means of the clock signal; a filter device, the pulse energy signal and the clock signal being passed into said filter device, said filter device having: a comparator device for comparing a voltage of the pulse energy signal with at least one predefinable threshold value condition and generating a logic result signal; a gate, to which the clock signal is passed, said gate being controlled by means of the logic result signal and thereby generating and outputting a retrieval signal; and an adjustable voltage source outputting an energy control signal with a voltage in accordance with a predefinition for a control voltage.

2. The apparatus according to claim 1 , wherein: said comparator device evaluates the predefinable threshold value condition having a lower limit threshold value; and the logic result signal assumes a value TRUE, if a voltage of the pulse energy signal exceeds the lower limit threshold value, and otherwise assumes a value FALSE, or alternatively the logic result signal assumes the value TRUE if the voltage of the pulse energy signal falls below the lower limit threshold value, and otherwise assumes the value FALSE.

3. The apparatus according to claim 2 , wherein said comparator device evaluates the predefinable threshold value condition which includes a predefined voltage range, and the logic result signal assumes the value TRUE if the voltage of the pulse energy signal lies in the predefined voltage range, and otherwise assumes the value FALSE, or alternatively the logic result signal assumes the value FALSE if the voltage of the pulse energy signal lies in the predefined voltage range, and otherwise assumes the value TRUE.

4. The apparatus according to claim 1 , further comprising a beam guiding device, said control device controlling said beam guiding device in a manner adapted to the pulse energy signal and the clock signal.

5. The apparatus according to claim 1 , wherein said filter device has: an energy control signal output; and a changeover device and, in one switching state, designated as filter state, said adjustable voltage source is connected to said energy control signal output and, in another switching state, designated as bypass state, the pulse energy signal received at said energy control input is passed to said energy control signal output and said gate is controlled such that the retrieval signal is identical to the clock signal.

6. The apparatus according to claim 1 , wherein the laser processing apparatus is used for laser marking of a document produced as a plastic object.

7. The apparatus according to claim 1 , wherein said filter device has: a retrieval signal output; an energy control signal output; and a changeover device and, in one switching state, designated as filter state, said adjustable voltage source is connected to said energy control signal output and, in another switching state, designated as bypass state, the pulse energy signal received at said energy control input is passed to said energy control signal output and said gate is controlled such that the retrieval signal is identical to the clock signal.

8. The apparatus according to claim 7 , wherein said gate is controlled such that the clock signal is passed to said retrieval signal output.

9. A filter device for laser driving of a pulsed laser being controllable with regard to laser pulse energy and a temporal retrieval of laser pulses, the pulsed laser having an energy control input for receiving an analog signal with a voltage for controlling the laser pulse energy, and a retrieval input for receiving a signal by means of which a retrieval of the laser pulses is controllable temporally, the filter device comprising: a pulse energy input for receiving a pulse energy signal which, in a manner temporally correlated with a clock signal assumes voltage values representing pulse energy for the laser pulses retrievable by means of the clock signal; a clock signal input for receiving the clock signal; an energy control signal output; a retrieval signal output; a comparator device for comparing a voltage of the pulse energy signal with at least one predefinable threshold value condition and generating a logic result signal; a gate receiving the clock signal and controlled by means of the logic result signal and thereby generating a retrieval signal and outputting the retrieval signal at said retrieval signal output; and an adjustable voltage source outputting an energy control signal with a predefinable control voltage at said energy control signal output.

10. The filter device according to claim 9 , further comprising a changeover device and, in one switching state, designated as filter state, said adjustable voltage source is connected to said energy control signal output and, in another switching state, designated as bypass state, the pulse energy signal received at said energy control input is passed to said energy control signal output and said gate is controlled such that the retrieval signal generated is identical to the clock signal, or the clock signal is passed to said retrieval signal output.

11. A method for controlling a pulsed laser controllable with regard to pulse energy and a temporal retrieval of laser pulses, during material processing of an object including during a marking of a plastic-based document, which comprises the steps of: comparing a pulse energy signal which, in a manner temporally correlated with a clock signal assumes voltage values representing the pulse energy for the laser pulses for processing with a threshold value condition and generating a logic result signal; passing the clock signal to a gate; controlling the gate by means of the logic result signal and generating a retrieval signal thereby; providing an energy control signal having a voltage in accordance with a predefinition for a control voltage; and using the retrieval signal and the energy control signal for controlling the pulsed laser.

12. The method according to claim 11 , which further comprises driving the pulsed laser at times in a bypass method mode, in which the pulse energy signal is used as the energy control signal and the clock signal is used as the retrieval signal.

13. The method according to claim 11 , which further comprises controlling a beam guiding device in a manner adapted to the pulse energy signal and the clock signal to position the laser pulses retrieved by the pulsed laser on the object in a controlled manner.

14. The method according to claim 13 , which further comprises: subjecting processing information to high-pass filtering and creating edge processing information in the process; firstly outputting the pulse energy signal in accordance with the processing information and subsequently it is output in accordance with the edge processing information; driving the beam guiding device such that the laser pulses assigned to a same processing position are emitted in accordance with the processing information and the edge processing information congruently successively onto the workpiece; and driving the pulsed laser during the outputting of the pulse energy signal in accordance with the processing information by means of a bypass method mode, and otherwise it is not driven thus.